1. Field of the Invention
One embodiment of the present invention relates to a display device. One embodiment of the present invention relates to a method for manufacturing a display device. In particular, one embodiment of the present invention relates to a display device including a liquid crystal element and a method for manufacturing the display device.
Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device, an input/output device, a driving method thereof, and a manufacturing method thereof.
In this specification and the like, a semiconductor device generally means a device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, and the like are each one embodiment of a semiconductor device. An imaging device, an electro-optical device, a power generation device (including a thin film solar cell, an organic thin film solar cell, and the like), and an electronic device may each include a semiconductor device.
2. Description of the Related Art
As one of display devices, there is a liquid crystal display device provided with a liquid crystal element. For example, an active matrix liquid crystal display device, in which pixel electrodes are arranged in a matrix and transistors are used as switching elements connected to respective pixel electrodes, has attracted attention.
For example, an active matrix liquid crystal display device including transistors, in which a metal oxide is used for a channel formation region, as switching elements connected to respective pixel electrodes is already known (Patent Documents 1 and 2).
It is known that an active matrix liquid crystal display device is classified into two major types: transmissive type and reflective type.
In a transmissive liquid crystal display device, a backlight such as a cold cathode fluorescent lamp or a light-emitting diode (LED) is used, and optical modulation action of liquid crystal is utilized to select one of the two states: a state where light from the backlight passes through liquid crystal to be output to the outside of the liquid crystal display device and a state where light is not output to the outside of the liquid crystal display device, whereby a bright or dark image is displayed. Furthermore, those images are combined to display an image.
In a reflective liquid crystal display device, optical modulation action of liquid crystal is utilized to select one of the two states: a state where external light, that is, incident light is reflected on a pixel electrode to be output to the outside of the device and a state where incident light is not output to the outside of the device, whereby a bright or dark image is displayed. Furthermore, those displays are combined to display an image. Compared with the transmissive liquid crystal display device, the reflective liquid crystal display device has the advantage of low power consumption since the backlight is not used.